Add XAttr to Link struct

[lawmurray]

This simply adds an XAttr field to the Link struct, as the JSON response for links (in e.g. ListChildren()) contains such a field, and it can be used to obtain the size and modification time of the original plaintext (not encrypted) file without further API calls, which can offer some big performance improvements (ref. rclone/rclone#8058).

From my tests, it exactly matches the XAttr field of the active revision obtained with ListRevisions().

(Side note: The active revision data included in the link JSON has an empty XAttr field, which may seem a little odd, but presumably it's because it would be redundant with the link's XAttr field, so there's no need to repeat it.)

[henrybear327]

Hey @lawmurray thanks for the PR!

Can you confirm that you have run the integration test on the rclone side when this change is in place?

Thank you!

[lawmurray]

Yes, if by rlcone integration tests you mean go test -v in the backend/protondrive directory. That all works as before.

[lawmurray]

Is there anything more that you need from me to merge this and the related PR @henrybear327? Would be nice to get this work included in the rclone 1.69 milestone that's due by 20 October.

[henrybear327]

Is there anything more that you need from me to merge this and the related PR @henrybear327? Would be nice to get this work included in the rclone 1.69 milestone that's due by 20 October.

Hey @lawmurray,

Sorry for missing this email notification completely :(

I am in the process of moving this repo under the rclone org umbrella, so you can merge things directly soon!

Henry

[lawmurray]

Okay, thanks @henrybear327.

This particular pull request is almost trivial by the way, it just adds an attribute to a struct needed to get at the new information, and the other pull request that you already merged (henrybear327/Proton-API-Bridge#28) depends on it.